This invention is concerned with a drug bioaffecting body-treating process that employs members of the general xe2x80x9cazapironexe2x80x9d structural class of psychotropic agents. The archetypical compound of the azapirone class of agents has the following structural formula 
and is known as buspirone. The hydrochloride salt has been referred to in the prior art as MJ 9022-1 and as buspirone hydrochloride. Other acid addition salts thereof are named by combining xe2x80x9cbuspironexe2x80x9d with the appropriate word to define the acid from which it is prepared as in xe2x80x9cbuspirone hydrochloridexe2x80x9d. The latter is the United States Adopted Name (USAN); refer to J. American Med. Assoc. 225, 520 (1973).
The synthesis of the compound and the disclosure of its psychotropic properties are described in the following patents and publications.
1. Y. H. Wu, et al., J. Med. Chem., 15,477 (1972).
2. Y.H. Wu, et al., U.S. Pat. No. 3,717,634 which issued Feb. 20, 1973.
3. L. E. Allen et al., Arzneium. Forsch., 24, No. 6, 917-922 (1974).
4. G.L. Sathananthan, et al., Current Therapeutic Research, 18/5, 701-705 (1975).
5. Y. H. Wu, et al., U.S. Pat. No. 3,976,776, issued Aug. 24, 1976.
The following patent references disclose and claim additional uses that relate to buspirone""s pharmacological effects on the central nervous system.
6. The use of buspirone hydrochloride as a novel antianxiety agent for the treatment of neurotic patients is described in G. P. Casten, et al., U.S. Pat. No. 4,182,763, issued Jan. 9, 1980.
7. Allen, et al., disclose the use of buspirone in treating extrapyramidal motor disorders in U.S. Pat. No. 4,438,119, issued Mar. 20, 1984.
8. Buspirone""s use in sexual dysfunction was described by Othmer, et al., in U.S. Pat. No. 4,640,921, issued Feb. 3, 1987.
9. Kurtz, et al., in U.S. Pat. No. 4,634,703, issued Jan. 6, 1987 disclose buspirone""s use in treating panic disorders.
10. Alderdice discloses the use of buspirone in the improvement of short term memory in U.S. Pat. No. 4,687,772, issued Aug. 18, 1987.
11. U.S. Pat. No. 4,777,173, issued Oct. 10, 1988 to Shrotriya and Casten, discloses and claims the use of buspirone in treating alcohol abuse.
Buspirone and related members of the azapirone class of psychotropic agents share common pharmacological actions, due perhaps to similar interactions of these compounds with monoaminergic pathways in particular areas of the brain. Specifically, functional binding of these agents at monoaminergic receptor sites in the brain indicate a more or less common neuropharmacologic profile for azapirones that would render members of the class useful equivalents when applied to pharmacological applications involving neural mechanisms.
The present invention resulted from the unexpected discovery that the representative azapirone, buspirone, was effective in treating patients suffering from sleep apneas. The only literature relating to the effects of any of the azapirones on respiration in general, concerned disclosures that buspirone had a stimulatory effect on respiration both in cats (Garner, et al., Am. Rev. Respir. Dis., 137:4, pages 946-950 (1989)) and in normal male volunteers (Rapoport, et al., Fed. Am. Soc. Exp. Biol., J 2:5, Abstract 7030 (1988).
It has become apparent that sleep apneas comprise a spectrum of related disorders with varying severity and morbidity. Sleep apneas have been usually classified as being an obstructive, central, or mixed apnea, depending on the presence or absence of respiratory efforts during the periods in which airflow has ceased. Obstructive and mixed apneas occur with greatest frequency with the most familiar being obstructive sleep apnea syndrome in which sporadic recurring collapse of the patient""s upper airway occurs during sleep. If the collapse is complete there is no air exchange at the nose and mouth and breathing is interrupted. The usual result is a partial arousal from sleep and a return to normal breathing. The patient in most instances has no knowledge or memory of these apnea episodes but finds himself constantly suffering from fatigue and daytime sleepiness for no apparent reason. These recurrent apnea episodes with resultant hypoxemia and fragmented sleep can have serious neurologic and cardiac consequences. In recent years there has been a growing awareness of the seriousness of the sleep apnea problem due to its wide occurrence and the lack of a recognized effective treatment.
Surgical and mechanical interventions as well as oxygen administration have been employed as treatments. None of these are very suitable. Treatment of sleep apneas by pharmacological intervention has also had little success. Respiratory stimulants, theophylline, antidepressants and progestational agents have been used to treat sleep apneas but have not been found to be very effective.
In sum, there is nothing in the prior art, including the specific references set forth hereinabove, that would suggest the use of buspirone or other azapirones for the treatment of sleep apneas.
The method of the present invention is intended for the treatment of patients suffering from sleep apneas. The method essentially involves administration of an azapirone; buspirone is preferred, or a pharmacologically acceptable acid addition salt thereof; to a patient in need of such treatment. For use in the instant method oral administration of a dose of from about 10 to 60 mg of an azapirone at the hour of sleep is usually employed.